In a vehicle as a mobile body, various electronic apparatuses such as a lamp like a head lamp and a tail lamp, and a motor like a starter motor and a motor for an air conditioner are generally mounted.
For supplying electric power to the various electronic apparatuses, a junction block is arranged at a suitable position in the vehicle. The junction block is formed by integrating various electric circuit elements like many fuses and relays.
Since the junction box includes fuses, relays and bus bars, the junction box is called as a fuse block or a relay box or an electric connecting box generically. In the specification, an electric connection box (for example, shown in Patent Document 1) is a generic name for the fuse block, the relay box and junction block.
An electric connection box shown in Patent Document 1 includes a box main body forming an outer shell, a fusible link mounted at the box main body, a bus bar arranged in the box main body, an upper cover covering a top of the box main body and a lower cover covering bottom of the box main body. The box main body includes a frame-shaped main body and a plurality of cassette blocks received in the main body, as mount sections, in which electric components like the relays and the fuses are arranged. On a top surface of the cassette block, the above-mentioned electric components are arranged. A connector of a wiring harness connected to the various electronic apparatuses mounted at the vehicle is fitted at a bottom surface of the cassette block.
The fusible link includes a fuse circuit body and a housing. The fuse circuit body includes an electric power input portion, a plurality of output terminals and a fusible body connecting the electric power input portion and each of output terminals. Electric power from an electric power source such a battery or an electric power generator is supplied through the bus bar into the electric power input portion. Terminal joined with an end of an electric wire of the wiring harness is connected with the output terminal which is connected through the electric wire to the electronic apparatus. The fusible body is blown out to isolate electrically the electric power input portion and the output terminals when electric current more than a predetermined electric current value flows therethrough. When electric current less than the predetermined electric current value flows through the fusible body, the fusible body is not blown out so as to maintain electric connection between the electric power input portion and the output terminals, so that the electric power is supplied through the electric power input portion to the electronic apparatuses.
The housing is made of an electric insulation synthetic resin and includes a flat box-shaped housing main body and a transparent cover closing an opening of the housing main body. The housing main body receives remaining portion other than ends of the electric power input portion and the output terminals . The housing main body is provided with the opening to expose the fusible body. The transparent cover is made of transparent synthetic resin and formed into flat plate shape and arranged at the housing main body so as to close the opening. The transparent cover enables to determine visually from an outside whether or not the fusible body is blown out.
The fusible link structured above is mounted at one cassette block from the plurality of cassette blocks.
The bus bar is formed by punching a sheet metal and bending it, and arranged plurally. The plurality of bus bars is received in the cassette blocks. One of the plurality of bus bars is joined with an electric cable connected to the electric power source. The bus bars in the plurality of cassette blocks are connected to each other according to a predetermined connecting pattern. The bus bar in each cassette block connects the fusible links and each electric wire of the wiring harness according to the predetermined connecting pattern when electric components and fusible links to be mounted in the cassette blocks are mounted in the cassette blocks.
The above-mentioned electric connection box, to which the electric power from the electric power source is supplied through a power supply cable, distributes the electric power by the bus bars in the plurality of cassette blocks and through the electric wires of the wiring harness after flowing the fuses, relays and the fusible links toward various electronic apparatuses.
Citation List
Patent Document 1: Japan Patent Publication Application No. 2001-211525